Bromide elevation in surface freshwater is unavoidable due to climate change and anthropogenic activities. Freshwater impaired by algal activity and bromide elevation has become problematic worldwide. However, studies of their impact on water quality and treatment practices are limited. This study is the first to demonstrate that genera of freshwater algae (e.g., cyanobacterium Microcystis aeruginosa and green alga Chlorella sp.) can accumulate bromine within their intracellular organic matter (IOM) when bromide occurs in water (i.e., 0, 0.5, 1, and 4 mg/L), which substantially enhances brominated disinfection byproduct (Br-DBP) formation upon chlorination. Using energy-dispersive and X-ray photoelectron spectrometers, we discovered clear bromine signals on algal surfaces in both cultures and natural water. Bromide elevation in source water particularly increased bromine accumulation inside algae cells and intracellularly, with greater than 33%–85% found in IOM. This phenomenon dramatically increased Br-DBP formation from Br-rich IOM precursors to ∼80% of total DBPs at an elevated Br^– level of 4 mg/L, resulting in the exponential rise of toxic potency of chlorinated water. These findings are significant to understand the origins of natural organic bromine in freshwater environments and provide further insights into how the co-impairment of algae and bromide elevation may influence finished water quality upon chlorination.

中文翻译：

---

在溴化环境下生长的淡水藻类细胞内有机物中溴的增加及其对DBP前体特性的影响

由于气候变化和人为活动，地表淡水中的溴化物升高是不可避免的。受藻类活动和溴化物升高损害的淡水在世界范围内已成为问题。但是，关于它们对水质和处理方法的影响的研究是有限的。这项研究是第一个证明淡水藻属（例如，蓝藻微囊藻和绿藻小球藻）的属。当水中存在溴化物（即0、0.5、1和4 mg / L）时，溴化物会在细胞内有机物（IOM）中积聚溴，从而大大增强了氯化后溴化消毒副产物（Br-DBP）的形成。使用能量分散和X射线光电子能谱仪，我们在培养物和天然水中的藻类表面发现了清晰的溴信号。水源中的溴化物升高尤其增加了藻类细胞内部和细胞内的溴积累，在IOM中发现的含量超过33％–85％。在升高的Br ^–浓度为4 mg / L，导致氯化水的毒性潜力呈指数增长。这些发现对于理解淡水环境中天然有机溴的来源具有重要意义，并为藻类和溴化物共存的损害如何影响氯化后的最终水质提供了进一步的见解。